1. Field of the Invention
The present invention relates to a train control system, and more specifically, relates to a train control system of detecting a train location by using radio distance measurement and controlling the train.
2. Description of Related Art
Conventionally, in a train control system using a so-called radio distance measurement system, a vehicle radio set is mounted on a train, a wireless network is formed between the vehicle radio set and a plurality of wayside radio sets which is disposed along a wayside of a track on which the train travels, and then, wireless radio propagation delay (time) between an on-board antennal of the vehicle radio set and a wayside antenna of the wayside radio set is measured, to detect a train location, so that train control is performed on the basis of the detected train location.
As a train control system using such a radio distance measurement system, conventionally, for example, a technique including: wireless train location detecting unit that detects a train location on a predetermined track on the basis of a propagation time of a radio wave between a vehicle radio set mounted on a train traveling on the predetermined track and a ground radio set disposed at a predetermined location on the ground; a travel distance calculating unit that calculates a travel distance of the train on the predetermined tack on the basis of an output signal of a speed generator (tachometer generator) connected to an axle of the train; a temporary reference location setting unit that sets the train location detected by the wireless train location detecting unit as a predetermined temporary reference location; and train location detection calculating unit that detects a train location on the predetermined track on the basis of the temporary reference location set by the temporary reference location setting unit and on the basis of the travel distance calculated by the travel distance calculating unit, has been disclosed (refer to, for example, Japanese Laid-open (Kokai) Patent Application Publication No. 2007-331629).
However, in the conventional technique, generally, a railroad track is divided into a plurality of control sections, wayside radio sets which control in each control section are set, and a ground device which controls the wayside radio sets in each control section allocates communication resources such as communication timings and frequencies to all of trains controlled in the control section. There is a problem such that the number of trains to which the communication resources can be allocated in one control section is limited. Consequently, in the case in which the number of trains entering a control section exceeds the controllable number of trains, the communication resources cannot be allocated to the train, and the train cannot be controlled. Therefore, there is a problem that the train is controlled to be stopped by a security function.
In the case in which the control section is set between stations, in order to prevent the number of trains from exceeding the controllable number of trains, a train has to be stopped before a control section, and it causes deterioration in passenger service. Furthermore, for example, there is another problem such that when a train is stopped in an air section of an overhead contact line, the overhead contact line is damaged.